[vsnet-grb-info 13876] GRB 130831A: Maidanak optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15190
SUBJECT: GRB 130831A: Maidanak optical observations
DATE:    13/09/08 00:17:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Pozanenko (IKI), A. Volnova (IKI), B. Hafizov (UBAI), O. Burhonov 
(UBAI) report on behalf of larger GRB follow-up collaboration:

We observed the afterglow  (Hagen et al., GCN  15139; Guidorzi et al., 
GCN 15140) of the Swift GRB 130831A (Hagen et al., GCN  15139)  with 
AZT-22 telescope equipped with SNUCAM of Maidanak observatory in R 
filter.  A preliminary photometry of combined images is based on  SDSS 
stars (see at the bottom):

T_start              T0+       Filter, Exposure, OT
(UT)                 (mid, d)            (s)

2013-09-02T13:58:23  2.0410    R       1x600     22.20 +/- 0.10
2013-09-04T18:47:13  4.2555    R       5x600     22.53 +/- 0.07
2013-09-05T18:57:03  5.2658    R       6x600     22.90 +/- 0.07

A preliminary lc of the afterglow GRB 130831A based on our GCNs ##15185, 
15186, 15188, 15189  and reported in this circular can be found in 
http://grb.rssi.ru/GRB130831A/grb130831A_lc_preliminary.PNG

A power-law decay of the lc between 0.1 days and 2 days after trigger is 
-1.68 +/- 0.06  and marginally consistent with power-law decay reported 
by Watson (GCN 15179).

Reference stars

N	SDSS id			R(Lupton)errR
1	J235443.71+292539.3	13.491	 0.016
2	J235438.60+292547.3	14.136	 0.015
3	J235423.64+292452.8	17.120	 0.016